〔Abstract〕 Objective To investigate the role of scavenger receptor A member 3(Scara3) in the phagocytosis of multi-walled carbon nanotubes(MWCNT) and cytokine production. Methods Under addition or without serum, expression of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β) and IL-6, and phagocytosis of MWCNT were compared between the control(NC) and knockdown group(Scara3 k/d) cells. Results Compared with the presence of serum, when there was without serum, the expression of TNF-α, IL-1β, and IL-6 and the uptake of MWCNT in the NC group and Scara3 k/d group all decreased after MWCNT stimulation. Compared with NC group, whether with serum or without serum, Scara3 k/d significantly reduced the expression of TNF-α, IL-1β and IL-6 induced by MWCNT and the uptake of MWCNT. Conclusion Scara3 mediates phagocytosis of MWCNT and cytokine production in macrophages.